PRIMECLUSTER Global File Services Configuration and Administration Guide 4.2 (Solaris(TM) Operating Environment)

5.3.1 Backing up by executing dd command

This section explains the procedure for backing up the GFS Local File System by using dd command.

The entire file system can be backed up by using dd command. The dd command is most suitable for backing up the entire GFS Local File System, since it can back up the entire file system faster than a backup in units of single files. However, the file system cannot be restored in units of single files in this case.

When performing a backup with the procedure below, confirm first that the GFS Local File System has been unmounted.

• Backup for a single-partition configuration

  Use the sfxinfo command to display partition information and check that a single partition is used (all of the respective file names are identical) is used and that it is smaller than the total tape capacity. Estimate the total capacity for the partition by adding 1 megabyte to the total of the values that are displayed in the size field (in kilobytes) .

  Example:The following is an example for the case of a single-partition configuration:

# sfxinfo /dev/sfdsk/gfs/dsk/vol0301

ID    special                      size     mount    type

0     /dev/sfdsk/gfs/dsk/vol0301(3f40021)   12626    /mnt     META

0     /dev/sfdsk/gfs/dsk/vol0301(3f40021)  113992    /mnt     DATA

0     /dev/sfdsk/gfs/dsk/vol0301(3f40021)    5120    /mnt     LOG

# dd if=/dev/sfdsk/gfs/rdsk/vol0301 of=/dev/rmt/0 bs=1024k

• Backup for a multi-partition configuration

  The dd command performs a backup for single partitions. Therefore, when a multi-partition configuration is used, the file system must be backed up in units of single partitions. After checking the partition configuration with the sfxinfo command, back up each of the partitions in the same way as for a single-partition configuration.

  Example: The following is an example of a 3-partition (META+DATA, DATA, and LOG) configuration:

# sfxinfo /dev/sfdsk/gfs/dsk/vol0301

ID    special                      size     mount    type

0     /dev/sfdsk/gfs/dsk/vol0301(3f40021)   25986    /mnt     META

0     /dev/sfdsk/gfs/dsk/vol0301(3f40021)  105751    /mnt     DATA

1     /dev/sfdsk/gfs/dsk/vol0302(3f40022)    5120    /mnt     LOG

2     /dev/sfdsk/gfs/dsk/vol0303(3f40023)  131736    /mnt     DATA



# dd if=/dev/sfdsk/gfs/rdsk/vol0301 of=/dev/rmt/0 bs=1024k -> Tape 1

  Tape replacement

# dd if=/dev/sfdsk/gfs/rdsk/vol0302 of=/dev/rmt/0 bs=1024k -> Tape 2

  Tape replacement

# dd if=/dev/sfdsk/gfs/rdsk/vol0303 of=/dev/rmt/0 bs=1024k -> Tape 3

• All the partitions making up the desired GFS Local File System must be backed up. Only backing up only some of the partitions cannot restore a file system.
• The tapes used for backing-up must be labeled so that the backed up partitions can be identified. They must then be stored as a set.

The dd command does not support multi-volume tapes. If the size of a file system is larger than the capacity of a single tape volume, divide the file system into multiple units and back these units up separately. In this case, set bs (block size) and count (block count) to an adequate value and increase iseek (input-file offset [block count]) by the count (block count).

Example: A partition is divided into one-gigabytes units to be backed up.

# dd if=/dev/sfdsk/gfs/rdsk/vol0301 of=/dev/rmt/0 bs=1024k count=1024

    -> Tape 1

  Tape replacement

# dd if=/dev/sfdsk/gfs/rdsk/vol0301 of=/dev/rmt/0 bs=1024k count=1024 iseek=1024

    -> Tape 2

  Tape replacement

# dd if=/dev/sfdsk/gfs/rdsk/vol0301 of=/dev/rmt/0 bs=1024k count=1024 iseek=2048

    -> Tape 3

  Tape replacement

# dd if=/dev/sfdsk/gfs/rdsk/vol0301 of=/dev/rmt/0 bs=1024k count=1024 iseek=3072

    -> Tape 4

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